The invention relates to an image pickup device which is adapted for permitting the construction of an optical image reading device such as may be used for reading documents which are both small in size and low in manufacturing cost.
Heretofore, a MOS photodiode array or a CCD (charge-coupled device) had been employed as an image pickup device in a facsimile transmission device or the like. Since such image pick-up devices are manufactured by IC techniques, the size of the image pickup element itself is small. Therefore, in reading an original document, the image must be reduced in size using a lens. Accordingly, the alignment of the image pickup element with the optical system must be precise. In addition to this problem, it has hitherto been difficult to reduce the overall size of the image pickup device.
A system for reading an original document has been known in the art in which the size of the image pickup elements corresponds to the width of the original document to be read and an optical fiber array or a lens array is employed as an optical system for effecting one-to-one image formation. In such a system, the image pickup elements are formed on an insulating substrate such as a glass plate by subjecting a photoconductive semiconductor to vacuum evaporation using a mask. According to this system, the optical path for image formation is short so that therefore it is possible to miniaturize the device. However, the system is still disadvantageous in that the circuit required for scanning and driving the image pickup elements is ordinarily quite bulky. That is, in order to scan the image pickup element, it is necessary to provide as many switching elements as there are arrays of image pickup elements. Accordingly, a large space for incorporating a number of switching elements is required and the number of connecting conductors is increased which in turn prevents the miniaturization of the device.
Furthermore, in the conventional system, thin conductors or conductors on a flexible sheet are used to connect the image pickup elements to the drive circuit. Accordingly, it takes a relatively long time to inspect the wiring and the associated manufacturing costs are high.
This invention is intended to eliminate the above-described difficulties accompanying a conventional image pickup device so as to provide a reading device both small in size and simple in construction.
An object of the invention is to improve the durability of an image pickup device against external conditions such as for instance vibration by providing intricate wiring associated therewith on the same substrate as the image pickup device itself.
Another object of the invention is to make it possible to employ photoetching or screen printing techniques for matrix wiring thereby to improve the manufacturing productivity of the device.
A further object of the invention is to make it possible to optically inspect a matrix wiring section thereby to simplify the inspection process.